This invention relates to takraw balls and it particularly relates to an improved takraw ball with regard to playability and safety.
Sepak Takraw is played by opposing teams passing a takraw ball across a chest-high net using feet, knees, head, shoulders etc., i.e. every part of the body except the player's hands and arms. The object of the game is to ground the ball in the opposing team's court; the rules of the game are similar to volleyball. Another form of takraw is hoop takraw, only one team plays at a time and the players co-operate to get the ball into a vertically orientated hoop some 5 meters above the ground.
United Kingdom Patent Specification No. 2,196,861 (Lorhpipat) describes the manufacture of traditional takraw balls by conventionally weaving split rattan strips into a spherical basket and the manufacture of takraw balls by forming strips of plastics material into interwoven hoops. As shown by FIG. 1, a takraw ball 1 has a spherical woven structure with a regular array of openings 2.
It is an essential characteristic of the takraw ball for it to be as inelastic as possible; this is to obtain the maximum energy transfer when the ball is struck so that the ball's flight or trajectory is as far, fast or high as possible. A takraw ball's bounce characteristic is much closer to the essentially inelastic collision between billiard balls than the elastic collision between a squash ball and racket. The woven structure of a takraw ball modifies its bounce characteristic, there is a small amount of relative movement between the strips that contributes to the essential "feel" of the ball, without which the ball is not a takraw ball.
A takraw ball may be defined by the below listed parameters:
weight=100 to 250 gm PA1 circumference=380 to 460 mm PA1 bounce=a first rebound of between 100 and 150 cm when dropped in free fall from a height of 330 cm. PA1 weight=170 to 180 gm PA1 circumference=420 to 440 mm PA1 bounce=a first rebound of between 130 to 135 cm and within a solid angle of 15.degree. when dropped in free fall from a height of 330 cm. PA1 a continuous or discontinuous outer layer of soft material with a springy backing; or PA1 a springy core embedded in a soft body. PA1 spring metal, nylon fibre, glass fibre, carbon fibre, engineering plastics. PA1 rubber, elastomer, thermoplastics elastomer (TPE), polyurethane, silicon rubber.
A competition sepak takraw ball must have the following parameters:
The drawback of both the conventional rattan takraw ball and the above-described plastics takraw ball is that their essential inelasticity makes them hard and playing takraw can be quite painful; especially for the novice. Clearly, this limits the popularity of the game as a participation sport. In addition, the hardness of the takraw ball can be dangerous. In conventional balls the rattan can unexpectedly break or splinter and cut the skin of a player. Similarly, the plastics takraw ball can break. Takraw can be played on almost any surface, not just the gymnasium floor of competition events, and some surfaces, such as concrete, can rapidly abrade/wear the surface of both types of ball; it is this that can lead to ball breakage.
U.S. Pat. No. 5,224,959 (Kasper) discloses a woven skeleton ball which is limited to "a plurality of loops woven together into a hollow spheroidal skeletal grid, said ball having an outer surface which is predominantly open space and thus making said ball suitable for allowing a user's fingers to pass through said surface and grip said loops" (see column 7 line 66 to column 8 line 2). This skeleton ball is clearly not a takraw ball, which is stated to have "a predominantly closed smooth surface with relatively few small openings" (see column 2, lines 37 to 39). It is evident that this skeleton ball cannot function or be used as a takraw ball. Its deformability or shape changing characteristic means that it cannot have an inelastic bounce characteristic. It probably has no bounce characteristic at all; whereas a takraw ball has to restore its original spherical shape after each collision.
U.S. Pat. No. 5,224,959 discloses composite materials, see FIGS. 3C and 3D and the related description at column 5 lines 8 to 27; however, there is no disclosure of the skeleton ball being bounceable, let alone selection of materials to produce a given bounce characteristic as required by the present invention.
It is one object of the present invention to provide a softer takraw ball whilst retaining the ball's essential characteristics. Conventional takraw balls are traditionally treated with coconut oil both to prevent the ball from rotting and to reduce the brittleness of the rattan, i.e. to make it softer and more playable. Experiments to simply make a plastics takraw from softer material were unsuccessful because the necessary bounce characteristic could not be achieved and the ball would not retain its woven structure when played, strips moved and overlapped one another.
Another object of the present invention is to provide a safer takraw ball.